Iodination of alkylbenzenes with iodine and silver nitrite

An Alternative to the Sandmeyer Approach to Aryl Iodides

“…The significant efforts devoted to iodoarene synthesis speak to the central roles these iodinated intermediates play in modern organic chemistry 1. A large number of reagents have been used for electrophilic aromatic iodination,2–6 including N ‐iodosuccinimide (NIS)7–12 and related NI compounds,13–17 iodine monochloride (ICl),18–20 bis(pyridine)‐iodonium(I) tetrafluoroborate (Py 2 IBF 4 ),21, 22 dichloroiodates,23, 24 NaI in combination with various oxidants,25, 26 and silver12, 27–30 or mercury31, 32 salts in combination with I 2 . A multitude of reagents and diverse reaction conditions are required to address a central problem in iodoarene synthesis by electrophilic aromatic substitution (EAS): the electrophilicity of “I + ” reagents must be matched with the overall “electron‐richness” of the arene to obtain selective iodine substitution.…”

“…This process, which incorporatesaphase separation that greatly simplifies product purification, is an attractive replacement for the Sandmeyer approach to iodoarenes that are otherwise difficult to access.The significant efforts devoted to iodoarene synthesiss peak to the central roles these iodinated intermediates play in modern organic chemistry. [1] Al arge number of reagents have been used fore lectrophilic aromatic iodination, [2][3][4][5][6] including N-iodosuccinimide (NIS) [7][8][9][10][11][12] and related NÀIc ompounds, [13][14][15][16][17] iodine monochloride (ICl), [18][19][20] bis(pyridine)-iodonium(I)t etrafluoroborate (Py 2 IBF 4 ), [21,22] dichloroiodates, [23,24] NaI in combination with variouso xidants, [25,26] and silver [12,[27][28][29][30] or mercury [31,32] salts in combination with I 2 .Amultitude of reagents and diverse reaction conditions are required to address ac entral problem in iodoarene synthesis by electrophilica romatic substitution (EAS): the electrophilicity of "I + "r eagents must be matched with the overall "electron-richness" of the arene to obtain selective iodine substitution. Once on the aromatic ring, the iodine substituenti sn ot strongly deactivating (Hammett s p = 0.18, s m = 0.35, s + = 0.14), [33] so trial and error must be used to find an iodine source which is sufficiently aggressive, but not so electrophilict hat multiple electrophilica romatic substitutions take place.…”

Advances in the direct iodination of aromatic compounds

“…Silver salts react with iodine to precipitate silver iodide and generate a reactive electrophilic iodine. Nitryl iodide (NO 2 I) can be generated by the action of silver nitrite on iodine 41 and this has been used to iodinate aromatic hydrocarbons although the reaction was accompanied by some nitration. However, when this reagent was used with steroidal alkenes, the structures of the products were rationalised 42 in terms of the formation of a nitro radical as the initial reactive species.…”

Bicyclic nucleoside inhibitors of Varicella–Zoster virus: The effect of branching in the p-alkylphenyl side chain

“…7). 7 Once all the necessary p-alkylaryliodides were successfully synthesised, they were subsequently coupled with EDU (17) in the presence of Pd(Ph 3 P) 4 , CuI and triethylamine to achieve the corresponding 5-arylethynyl-2 0 -deoxyuridines (31-38). A copper-catalysed cyclisation then led to the formation of bicyclic furanopyrimidine ring derivatives (7-14) (Fig.…”

“…Reagents and conditions: (i) ArI, Et 3 N, Pd(Ph 3 P)4 , CuI, DMF, rt, overnight; (ii) MeOH, CuI, reflux, 4 h.…”